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In the deep sea, most animals can make their own light: a large study off California found that about three quarters of them glow.

Marine biology (bioluminescence)

Science

The story behind the card

The figure comes from a 2017 study by Séverine Martini and Steven Haddock, who went through 17 years of underwater video from Monterey Bay, California, and found that 76 per cent of the animals seen between the surface and about 3,900 metres could produce light. Below about 1,000 metres no sunlight reaches at all. Most of this light comes from a chemical reaction in which a molecule called luciferin combines with oxygen, helped by an enzyme called luciferase. Anglerfish dangle a glowing lure to draw in prey. Many small fish and squid glow faintly on their bellies to blend with the dim light from above and hide their outline, a trick called counter-illumination. Others flash to startle attackers or leave a glowing cloud behind as they escape.

Türkçe oku
Derin denizlerde yaşayan hayvanların çoğu kendi ışığını üretebilir. Kaliforniya açıklarında yapılan geniş bir araştırma, bu hayvanların yaklaşık dörtte üçünün ışık saçtığını gösterdi.

Bu oran, Séverine Martini ile Steven Haddock'un 2017'de yayımladığı bir çalışmadan geliyor. İki araştırmacı, Kaliforniya'daki Monterey Körfezi'nde 17 yıl boyunca çekilmiş su altı görüntülerini taradı ve yüzeyden yaklaşık 3.900 metre derinliğe kadar görülen hayvanların yüzde 76'sının ışık üretebildiğini buldu. Yaklaşık 1.000 metrenin altına hiç güneş ışığı ulaşmaz. Bu ışığın çoğu kimyasal bir tepkimeden doğar: Lusiferin denen bir molekül, lusiferaz adlı bir enzimin yardımıyla oksijenle birleşir ve ışık saçar. Fener balıkları avlarını parlayan bir yemle kendilerine çeker. Birçok küçük balık ve kalamar, karnının altından hafifçe ışıyarak yukarıdan süzülen soluk ışığa karışır ve aşağıdaki avcılara gölgesini belli etmez; buna karşı aydınlatma denir. Kimi türler de saldırganı ürkütmek için ansızın parlar ya da kaçarken arkasında ışıklı bir bulut bırakır.

Sources and further reading

Background reading: Bioluminescence
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